Classification And Screening For Cervical Dysplasia
Cervical dysplasia is commonly referred to as cervical intraepithelial neoplasia (CIN). It is often classified by the degree of penetration of abnormal cells into the tissue lining (epithelium):
- CIN I describes the involvement of the basal third of the epithelium.
- CIN II involves the basal two thirds of the epithelium.
- CIN III involves more than two thirds of the epithelium.
A diagnosis of cervical dysplasia does not necessarily mean that cervical cancer will develop. In fact, up to 74 percent of women with mild CIN will naturally regress to normal within five years (Holowaty 1999). Of those cases that do progress, only a minority of women will actually develop cancer.
- Only 1 percent of women with CIN I who experience progression will progress to severe dysplasia or worse (Holowaty 1999).
- Among patients with CIN II, 16 percent will advance to severe dysplasia within two years and 25 percent within five years.
- An overall progression rate of severe dysplasia (CIN III) to cervical cancer has been observed in 12 to 32 percent of patients (Arends 1998; McIndoe 1984).
Pap smears are the standard tool used to screen women for cervical dysplasia or cancer. During a Pap smear, cells are scraped from the cervix and then evaluated microscopically. About 5 to 7 percent of Pap smears yield abnormal findings (Jones 2000).
One major problem with screening is poor follow-up testing among women with abnormal Pap smears. In most cases, an abnormal Pap smear requires a follow-up test in a few months. However, an estimated 10 to 61 percent of women with abnormal Pap smears do not undergo follow-up testing (Shinn 2004). Factors associated with noncompliance include an elementary education, prior surgery, additional diseases, consumption of medications for chronic conditions, and family illness (Bornstein 2004).
In general, according to the American Cancer Society’s 2002 screening guidelines:
- Women should begin cervical cancer screening no later than three years after beginning vaginal intercourse but no later than 21 years of age.
- Cervical cancer screening should be performed annually with regular Pap tests or every two years with liquid-based Pap tests.
- A woman 30 years of age or older with three consecutive normal Pap smears may elect to be screened every two to three years.
- Women who have undergone hysterectomy can elect to discontinue Pap smears if the surgery was not performed to treat cervical cancer or precancer. Women with an intact cervix post hysterectomy should undergo screening until at least age 70.
- A woman older than age 70 may choose to discontinue Pap smear screening after three prior normal Pap smears and no abnormal results in the preceding 10 years.